# Relationship history for MSHA mine 3301456

Current hierarchy: **Straub Glenn F → Spring Industries Inc → Sandyville Pit**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Edgar Spring Inc → Sandyville Pit; 1950-01-01 to 1979-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Spring James E → Sandyville Pit; 1950-01-01 to 1979-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Spring James E → Edgar Spring Inc; 1950-01-01 to 1979-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Spring Industries Inc → Sandyville Pit; 1979-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Straub Glenn F → Sandyville Pit; 1979-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Straub Glenn F → Spring Industries Inc; 1979-11-01 to current/open; source msha-controller-operator-history